PACS development in Asia.

First, history of PACS in Japan from 1982 to 2002 has been investigated. By 2002 total of 1468 PACS units have been installed. Of these, 1174 are small-size PACS with less than four image display terminals, 203 are medium-size with 5-14 terminals, and 91 are large-size with 15 up to 1300 terminals. The main nine large-size PACS of 91 have been retrospectively investigated from 1984 for PACS experiments and from 1989 for PACS operation. Most of these nine hospitals have increased the number of PACS terminals by installing additional PACS units, instead of reinforcing the existing single PACS. The use of DICOM interfaces has increased the number of modalities connected to PACS and influenced the spreading of PACS installations in Japan. The status of HIS and RIS coupling to PACS, and the use of PACS in primary diagnosis or in image referral are discussed. Assessment of PACS is now in an early stage. Baseline studies of HIS/RIS/PACS effectiveness have been carried out to assess quantitatively the PACS merit. Second, history of PACS development in Korea is described. Very acute climbing up of filmless PACS diffusion was observed from 2000 to 2002. The reasons seem to be lack of domestic X-ray film industry, economic crisis in 1997 and PACS Reimbursement Act in health insurance in Korea. Third, the Hong Kong Wide Area Image Distribution/PACS Project is reported. It is now under phase 1 of design and partial implementation employing the latest and the highest ends of advanced technology such as failure resilience.

History of PACS in Asia.

First, history of PACS (picture archiving and communication system for medical use) in Japan is described in two parts: in part 1, the early stage of PACS development from 1984 to 2002, and in part 2 the matured stage from 2002 to 2010. PACS in Japan has been developed and installed by local manufacturers by their own technology and demand from domestic hospitals. Part 1 mainly focuses on quantitative growth and part 2 on qualitative change. In part 2, integration of PACS into RIS (radiology information system), HIS (hospital information system), EPR (electronic patient record), teleradiology and IHE (integrating healthcare enterprise) is reported. Interaction with other elements of technology such as moving picture network system and three dimensional display is also discussed. Present situation of main 4 large size hospitals is presented. Second, history of PACS in Korea is reported. Very acute climbing up of filmless PACS diffusion was observed from 1997 to 2000. The reasons for such evolution are described and discussed. Also changes of PACS installation and system integration with other systems such as HIS and role of them in radiological diagnoses in Korea since 2002 are described. Third, history in China is investigated by checking international academic journals in English and described as far as events are logically linked and consistently meaningful.

Workflow analysis of medical staff in surgical wards based on time-motion study data.

The aim of this study is to clarify the change over time in the elements of work (job elements) and their features, as well as the relationship between job elements and the type of job, job class, and the role of the hospital they are performed in. A time-motion study was conducted on the medical staff in the surgical wards of two hospitals. An analysis of roles bys by (a) type or class of job type, and (b) hospital function was conducted. The number of working hours was analyzed, as well as the ratio of working hours with respect to direct and indirect job elements. The job elements required for each medical staff member were proven to differ by type of job (doctors and nurses) and also by job class (nurse leaders and staff). When comparing between hospital the differences in job elements were proven not to be a result of differences in hospital function, but to result from the ward system (ward design and nursing system).

[Present and future of flat panel detectors in the world].

Present status of development of flat panel detectors and their clinical application in the world have been surveyed, and future trends are also explored especially in the field of material researches and methods of manufacturing. Also the importance of role of medical physicists on user side is described because characteristic physics measurement of a detector assembly is unavoidable and essential in quality assurance in clinical routine and acceptance test in hospitals. Even though physics measurements and clinical evaluations on flat panel detectors have shown remarkable progress and advances in these several years, future problems of cost down in manufacturing and quality assurance to prevent individual differences between detector assemblies must be resolved. Results of evaluation in mammography, chest radiography, fluoroscopy for cardiovascular examination, bone tumor examination and radiotherapy application indicate that flat panel detectors are future promising materials. Their systematic operation is contributing to heighten accuracy of image examinations and preciseness of radiation therapy. Encouragement to medical physicists relevant to flat panel detectors is also raised in this paper.

Development of a time-oriented data warehouse based on a medical information event model.

We designed a new medical information event model and developed a time-oriented data warehouse based on the model. Here, the medical information event in a basic data unit is handled by a medical information system. The timing of decision making and treatment for a patient in the processing of his medical information is sometimes very critical. The time-oriented data warehouse was developed, to provide a search feature on the time axis. Our medical information event model has a unique simple data structure. PC-ORDERING2000 developed by NEC, which used Oracle, had about 600 pages of tables. However, we reduced these 600 complicated data structures to one unique and simple event model. By means of shifting clinical data from the old type order entry system into the new order entry system of the medical information event model, we produced a simple and flexible system, and the easy secondary use of clinical data of patients was realized. Evaluation of our system revealed heightened data retrieval efficiency and shortened response time 1:600 at a terminal, owing to the 1:600 reduction of the number of tables as mentioned above.

Evaluation of video capture equipment for secondary image acquisition in the PACS.

There are many cases in which picture archiving and communication systems (PACS) are built with old-type existing modalities with no DICOM output. One of the methods for interfacing them to the PACS is to implement video capture (/ frame grabber) equipment. This equipment takes analog video signal output from medical imaging modalities, and amplitude of the video signal is A/D converted and supplied to the PACS. In this report, we measured and evaluated the accuracy at which this video capture equipment could capture the image. From the physical evaluation, we found the pixel values of an original image and its captured image were almost equal in gray level from 20%-90%. The change in the pixel values of a captured image was +/-3 on average. The change of gray level concentration was acceptable and had an average standard deviation of around 0.63. As for resolution, the degradation was observed at the highest physical level. In a subjective evaluation, the evaluation value of the CT image had a grade of 2.81 on the average (the same quality for a reference image was set to a grade of 3.0). Abnormalities in heads, chests, and abdomens were judged not to influence diagnostic accuracy. Some small differences were seen when comparing captured and reference images, but they are recognized as having no influence on the diagnoses.

Methodology development for quantitative optimization of security enhancement in medical information systems -Case study in a PACS and a multi-institutional radiotherapy database-.

The target of our study is to establish the methodology for analyzing level of security requirements, for searching suitable security measures and for optimizing security distribution to every portion of medical practice. Quantitative expression must be introduced to our study as possible for the purpose of easy follow up of security procedures and easy evaluation of security outcomes or results. Results of system analysis by fault tree analysis (FTA) clarified that subdivided system elements in detail contribute to much more accurate analysis. Such subdivided composition factors very much depended on behavior of staff, interactive terminal devices, kinds of service, and routes of network. As conclusion, we found the methods to analyze levels of security requirements for each medical information systems employing FTA, basic events for each composition factor and combination of basic events. Methods for searching suitable security measures were found. Namely risk factors for each basic event, number of elements for each composition factor and candidates of security measure elements were found. Method to optimize the security measures for each medical information system was proposed. Namely optimum distribution of risk factors in terms of basic events were figured out, and comparison of them between each medical information systems became possible.

Evaluation of the effect of varying MPEG-2 compression ratios on digital coronary angiographic assessment of stenosis severity.

The purpose of this study is to evaluate the influence of MPEG-2 compression scheme on coronary angiography and to search the highest compression ratio at which no significant effect to accuracy of assessment of stenosis severity occurs. Forty-Four digital cine angiographies were used. Three cardiologists participated in a subjective study in which they read both uncompressed images and compressed images. Furthermore, an objective study was carried out to measure vessel stenosis ratio by using software. The influence of compression was evaluated by kappa statistics in case of subjective study and by both systematic error and random error in case of objective study. Kappa statistics between uncompressed image and compressed image at a ratio of 80:1 was significantly lower than that of other compression ratios such as 40:1. Similar results were obtained in objective evaluation. In this report, the authors provide the baseline for further studies on observer performance for motion images.

An inductive method for automatic generation of referring physician prefetch rules for PACS.

To prefetch images in a hospital-wide picture archiving and communication system (PACS), a rule must be devised to permit accurate selection of examinations in which a patient's images are stored. We developed an inductive method to compose prefetch rules from practical data which were obtained in a hospital using a decision tree algorithm. Our methods were evaluated on data acquired in Osaka University Hospital for one month. The data collected consisted of 58,617 cases of consultation reservations, 643,797 examination histories of patients, and 323,993 records of image requests in PACS. Four parameters indicating whether the images of the patient were requested or not for each consultation reservation were derived from the database. As a result, the successful selection sensitivity for consultations in which images were requested was approximately 0.8, and the specificity for excluding consultations accurately where images were not requested was approximately 0.7.

Development of a system which automatically acquires optimal discrete-valued attributes by dividing and grouping continuous-valued attributes to assist clinical decision making in radiotherapy.

The purposes of this study were first to develop a system which statistically tests results of radiotherapy and which automatically acquires an optimal discrete-valued attribute by dividing and grouping continuous-valued attributes, and second to find the optimal range of values such as tumor dose by taking account of the conditions and statistics in ROGAD (Radiation Oncology Greater Area Database), a multi-institutional database in Japan. Our ultimate goal is to assist clinical decision making for every patient. In this research, two algorithms for acquiring a boundary value were developed without detecting false boundaries or accidental errors of acquired boundaries. The resolution of detected discrete-valued attributes and speed of convergence were confirmed to be practical. The optimal range of given tumor dose with the best reaction and with the fewest complications is expected to be clarified.

Development of a Virtual Private Database for a multi-institutional Internet-based Radiation Oncology Database overcoming differences in protocols.

A multi-institutional Radiation Oncology Greater Area Database (ROGAD) was started in 1991 under the direction of the Japanese Society for Therapeutic Radiology and Oncology (JASTRO). Use of ROGAD was intended to allow reflection of results of data analysis into treatment strategy and treatment planning for individual cases, to provide quality assurance, to maximize the efficacy of radiotherapy, to allow assessment of new technologies or new modalities, and to optimize medical decision making. ROGAD collected 13,448 radiotherapy treatment cases from 325 facilities during the period from 1992 to 2001. In 2000, questionnaires were sent to 725 radiotherapy facilities throughout Japan, to further obtain the situation of the radiation oncology database. Workers at 179 facilities replied that"the protocol of my facility is different from ROGAD protocol and I must send data according to the ROGAD protocol". So, we developed the Virtual Private Database System (VPDS) which is operated as if an oncologist had a database solely owned by his own facility, in spite of actually operating ROGAD. VPDS realizes integration of different plural databases, regardless of differences in entry methods, protocols, definitions and interpretations of contents of clinical data elements between facilities.